We demonstrate the existence of new nonrenormalizable ultraviolet divergences in bosonic nonlinear sigma models with the target-space metric corresponding to weak transverse gravitational waves. These infinities arise when the loop expansion is summed to all orders. For string theories they correspond to couplings of gravitons to massive fields.

• Received 19 May 1986

DOI:https://doi.org/10.1103/PhysRevLett.57.1511